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Engine more refined in Power Mode

Discussion in 'Gen 3 Prius Main Forum' started by briank101, Oct 7, 2013.

  1. briank101

    briank101 Member

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    I find when I accelerate quickly from a stop up to about 30 mph in Power Mode, the car accelerates with less engine noise (more refined) than in any other Mode (Normal or Eco). Has anyone else noticed this?
    I suspect in Power mode the electric motor is programmed to take on a greater share of the load earlier compared when in the other modes. While I know Power Mode is basically a more sensitive mapping of the pedal position vs throttle opening (power demand), but this may be the case only if one analyzes this from a static perspective on an xy graph, I'm guessing a dynamic analysis of the mapping (in Power Mode) would show less of a lag between pedal position and throttle opening, becauses no matter how fast I press the gas pedal in Normal or Eco mode, I never get that same refined "V8" engine tone response from the powertrain as I do in Power Mode. Note: I say V8 engine, but I would say the first 0.5 second response is even smoother than almost any V8 I've driven.

    I will say the Prius GenIII in Power mode from a stop up to 30 mph has about the smoothest most refined (no fuss) power delivery compared to almost any ICE car I've ever driven.
     
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  2. rdgrimes

    rdgrimes Senior Member

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    Power mode is nothing more than a re-mapping of the throttle response curve. You'll get the same thing in ECO or normal mode just by pushing harder/further on the pedal. If you floor it, all 3 modes are identical.
     
  3. cary1952

    cary1952 Member

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    It must be your imagination, but if it works for you , awesome!
     
  4. briank101

    briank101 Member

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    Note I am not talking about faster accleration. Yes 100% pedal depression in Eco mode is the same throttle postion as 100% pedal depression in Power Mode (but after how many milliseconds). That's not where I'm going with this. Are you going to say your proof is that all 3 modes get you to 60 mph in about the same time, no argument from me there either. As I said in the OP, I'm not talking about the static mapping of pedal depression vs throttle which can be easily Googled. I'm talking about bringing the time domain into it. Perhaps I should re-phrase, you start from a stop and it takes 0.2 seconds to reach 100% pedal position, at time 0.2 seconds, where is the actual throttle position in Eco Mode vs Power Mode, my guess is that there is a longer time lag in Eco mode reaching 100% throttle (not pedal position) than in Power mode. There is talk of "Damping" in the Eco mode in the Toyota press releases. This, I suspect, gives the engine more time to get up to high RPM in Eco mode as the throttle position (not the pedal postion) reach 100%, pedal is already at 100% travel. In Power mode, I suspect MG2 is producing max. power before the engine gets up to higher power rpms, hence the more refined note during max accelation up to about 20 to 30 mph. I know the more refined (not quicker) accleration is there, I just want to know if my reasoning for it is correct.

    Estimated Engine/MG2 load sharing at 0.2 sec at 100% pedal depression
    Power mode: 30%/70% of total 60 hp available at 0.2 seconds into the acceleration event
    Normal mode: 50%/70% of total 50 hp available at 0.2 seconds into the acceleration event
    Eco mode: 70%/30%of the total 40 hp available at 0.2 seconds into the acceleration event

    Note: lower hp value for Eco and Normal modes at 0.2 seconds due to slower damping as mentioned in Toyota releases. The damping slows the rate of system power increase in perhaps the first 0.5 seconds. All modes get to near max wheel horsepower perhaps by 40 or 50 mph which means little variation in overall 0-60 mph times.
     
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  5. fuzzy1

    fuzzy1 Senior Member

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    The pedal remapping is a static thing. I believe that briank101 is right that the dynamics also change, producing different time lags.

    From past discussions, it seems that the modes have different filtering of the pedal's time response. PWR has the least filtering, and the least delay from when the pedal is pushed until the throttle valve turns. ECO is fairly heavily filtered, so a twitchy foot or bump in the road has little effect. This filtering requires more time delay, so it takes longer until the throttle valve is commanded to open.

    I strongly suspect that the different filtering and time lag strongly contribute to the different feel many drivers report in PWR mode. Those who frequently press the pedal quickly are going to notice it far more than those who push it slowly and deliberately.
     
  6. jdcollins5

    jdcollins5 Senior Member

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    I have also noticed what briank101 is saying about MG2 applying more power, and earlier, at start in Power Mode. I also notice less transition from MG2 to ICE like I do in Normal Mode.

    I think this is the more refined feeling that he is referring to.
     
  7. briank101

    briank101 Member

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    If I wasn't so technically inclined, I'd would have left at perception. It's just everytime this comes up the answers are too simplistic. Duh. Look at the pedal to throttle mappings. I work as an EE and if we just looked at the static instead of the dynamic we'd still be in the 19th century. Everything (including a pulse through a conductor) takes time, we do TDR at work all the time. In the Prius we have 2 kinetic power sources with different with different dynamic rotary power characterics (responsiveness if you will) It's just that my Torque Android doesn't go capture data fast enough to capture the data to show the dynamic load sharing of each of the power components in that 0 to 100% time period, but even my kids notice the more refinded engine tone when I launch quickly in Power mode from a stop. Go try it. It's one of those few luxury car refinements I get when driving my Prius. The other thing I did was stop all the squeeks and rattle and now it's not a half bad car to drive.
     
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  8. CaliforniaBear

    CaliforniaBear Clearwater Blue Metallic

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    I have driven over 10 K miles in two different Prius models. I have never used the Power mode. I don't expect I ever will. The HSI does get into the PWR area quite often when in the HV mode. I like the accelerator control/response in the ECO mode which is always on.
     
  9. bisco

    bisco cookie crumbler

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    i think, because you have to push the pedal harder in eco mode to get the power you need, you tend to over rev the ice vs power mode. the throttle is probably smoother in power mode and easier to get where you want to be, especially if you drive it hard.
     
  10. rdgrimes

    rdgrimes Senior Member

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    That's all really just another way of saying the same thing. "Timing" is also related to the pedal response curve, since it takes time to push the pedal down. When you're talking about tenths of a second, you can't really separate one from the other. Since we're talking about fly-by-wire, the computer is possibly just performing the same actions in less time. I doubt many of us drive by slamming the pedal to the floor. Its always a more or less gradual pressing down of the pedal, and the response is based on vehicle speed and load.

    The same things are true of fly-by-wire braking and steering, meaning the faster/harder you provide the input - the more things happen. So in ECO mode you'd have to press the pedal faster/harder to get the same response as a slower pressing would provide in power mode. But since power mode will never do anything but waste gas and energy, I'm not sure why anyone would care.
     
  11. fuzzy1

    fuzzy1 Senior Member

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    No, it isn't. To an EE who has worked on control systems, these are separate and independent. One (the pedal response graph commonly posted here) is static (no time component), the other is dynamic.

    Since my reply, OP has now mentioned that he is also an EE, so he is speaking my language. I rarely use PWR, but believe he is on the right track.
     
  12. briank101

    briank101 Member

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    I now nearly always use the power mode, because I now find I can more easily tap into glide (no regen) without glancing at the HSI in that mode (must be the weight of my foot). I also launch accelerate from a stop pretty quickly as I found it's impact on mpg is so little it's not worth putting the effor there in the grand scheme of mpg reduction with emphasis on anticipatory braking in my now nearly 95% city driving, bringing far more mpg return for the effort. So I feel I now get the best of both worlds, high mpg (59 mpg) and fun driving (fast refined acceleration).

    I'm thinking put a bumper sticker on my car "High city mpg = Speeding up speedily and slowing down slowly". I know this lady at work who always accelerates her Prius like a "grandma" (actually she has grand-nieces), but always brakes at the last minute (along with using the brake pedal a few times a minute) and she can't understand why she only gets 42 mpg which of course is because drives with the same old mpg improvement myths that you still see most people using. Boy is she annoying to be behind on the road.
     
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  13. El Dobro

    El Dobro A Member

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    When the Gen III first came to the USA, Toyota touted the driving mode buttons and if you dug around on the web site, there was a little video that showed how the different modes worked and it stated that the battery gave an extra boost in Power mode. Now, the buttons are barely mentioned. On the Lexus site, it's stated that when Sport mode (their version of Power) is selected for the hybrids, the power to the motor is boosted to 650V. Also, on Toyota's technology page, if you look at the Power Control Unit, it says that the unit will boost the power up to 650V, as needed.

    Technology File | TOYOTA MOTOR CORPORATION GLOBAL WEBSITE
     
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  14. mediahound

    mediahound Active Member

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  15. Former Member 68813

    Former Member 68813 Senior Member

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    Interesting. Anyone measured 0-60 times in different modes?
     
  16. El Dobro

    El Dobro A Member

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    This video shows what happens in the different modes for a Lexus CT200h. In the Eco mode, the voltage is limited to 500V, while in Sport mode, the voltage is boosted to 650V.



    Now you would figure this is just because it's a Lexus, but according to testers, the CT200h and a Prius hatchback have the same acceleration figures.


    2011 Lexus CT 200h First Test - Motor Trend
     
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  17. El Dobro

    El Dobro A Member

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    I don't think anyone ever has. Usually the car mags just go for maximum acceleration figures.
     
  18. mediahound

    mediahound Active Member

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    Not sure why you are posting a video for an entirely different car.

    Here's one for the Prius:

     
  19. El Dobro

    El Dobro A Member

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  20. mediahound

    mediahound Active Member

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